Cycling computers have come a long way. For starters, most of them aren’t simple speedometers anymore. Sigma BC 1609 is no exception. It offers more features (especially cadence) than any other computer in its price category. And it does that without skimping on quality. And being a wired bike computer, it has none of the problems associated with wireless computers, like interference from front lights, other wireless computers, etc.

Being an owner of the older Sigma BC 1606L computer, I was glad to see the improvements in its successor, Sigma BC 1609. The 1609 model has a temperature function, which was absent in the older model. Also, the BC1609 rounds the current speed to one tenth of a mile (15.0 –> 15.1 –> 15.2) per hour. The older 1606L rounds them to the closest 0.5 mph (15.0 –> 15.5 –> 16.0). It never really bothered me, but for some people that was an inconvenience.

Included in the package are the following items:

Sigma BC 1609 computer.

One CR 2032 battery, which you’ll have to install yourself. Fortunately, you’ll only need a coin to open the battery compartment. If you’re a snob, use a gold coin.

Bracket (docking station, where the computer is mounted).

Magnet, you’ll attach it to a spoke.

Sensor, goes on the fork.

2 rubber rings.

Cadence kit: sensor and magnet.

Previous models like my BC1606L had the batteries installed by Sigma before packaging. They displayed the current time (standby mode) and the battery slowly discharged in some warehouse/bike shop, until someone bought them. That’s why I had to buy a new battery about a year after purchase. A friend of mine bought Sigma’s BC 1609 about a year ago. He commutes to work everyday, a 30-mile round trip. The battery is still alive and kicking. Don’t use the backlight all the time though, or you’ll need a lot more batteries than me! The neat thing is, when you change the battery, you won’t lose your valuable data!

Installation was easy. Both the computer’s docking station and sensor are mounted using rubber rings. These make the installation a snap. You’re worried that the rubber rings will eventually fail? Don’t. I’ve ridden my bikes in cold (-5 degrees F/ -20 C) and hot (102 F/ 39 C) weather, for thousands of miles, and the rubber rings are still in good shape. I even reused them recently when I installed the BC1609 on another bike. In addition to the rubber ring, the bracket is securely held in place by an adhesive tape that sticks to the handlebar (or stem).

The following official video from Sigma shows the BC1609 installation and initial computer setup. Sigma is a German company, that’s why the computer in the video is set to German and shows kilometres per hour, not miles. Don’t worry though, as the language can be set to English, and mph can be used instead of metric.

At first, navigating the menus might be confusing. But after a couple of rides, you’ll be pressing those buttons without even thinking about it.

Click on a thumbnail for a larger view. Press arrow keys or click on the left/right of the picture to see previous/next one.

For the price, Sigma BC 1609 offers a lot of features. Especially the cadence feature, which is very hard to find in similarly priced computers. You can get for $30 or so on Amazon.

Sigma BC 1609 Features:

Sigma BC 1609 General Functions:

Auto start/stop

MPH or KPH

Large display, font and icons easy to read

7 available languages

Integrated storage chip for data backup

Low battery indicator

2 adjustable wheel sizes for 2 bikes

Automatic recognition of bike 2

Backlight

Current temperature

Weatherproof

PC compatible

Bike Functions:

Current speed

Average speed

Maximum speed

Trip distance

Current/Average speed comparison

Total distance bike 1/bike 2/bike 1+2

Current and average cadence

Programmable trip section counter

Time Functions:

Ride time

Clock (12/24 hr)

Stopwatch

Countdown timer

Total ride time bike 1, bike 2 & bike 1+2

Is it really weatherproof? Yes! I rode twice in heavy rain, and my Sigma BC1609 is still alive. Last winter I rode when it was -5 F (-20C), and was amazed to see the computer’s display didn’t completely freeze! The LCD did slow down considerably, though.

Hello Tony,
as I said, max. allowed distance between sensor and magnet is only 0.5 cm (less then 1/5th of an inch), but when I install it, the gap is around 3 cm (1.18 inches). As a result, no speed is being measured and displayed. I’ll try to improvise something tomorrow. Will put a piece of rubber in between fork and sensor, bringing it closer to the magnet. Hope this will work.

@ hdi, I had an earlier model Sigma with the same issue and I did exactly what you are suggesting. I placed a bit of rubber under the sensor to to get it within range of the magnet and it worked fine. I just used a bit of double sided tape between the fork and sensor, and sensor and spacer to make sure it stayed in place.

If it’s a wireless Sigma bc1609, then you could try mounting the magnet on the rear wheel. But I suspect you have the wired one, so I’m not sure if the cable is long enough. When I installed this computer on my friend’s MTB, the distance from the sensor to the magnet was slightly more than the recommended 5mm. Worked fine, though. My suggestions:

1. Piece of rubber (duh!)
2. Mount it closer to the center of the wheel to lessen the gap
3. Use additional magnets on top of the original one. You can purchase rare earth magnets anywhere these days.
4. Mount it on the rear.

I’d be glad to see how you worked around this problem, so please post back. It would be great if you could upload some photos (in the form below), so others will benefit.
Computer installation is more challenging with MTBs. Some manufacturers allow even less than 5mm distance, so don’t be angry at Sigma!

Hello Tony and jolly_tas,
since my Sigma 1609 has wire, mounting it to the rear wheel was not an option. I did a combination of your suggestions:
1. I used a rather thin piece of rubber (folded it six times to get the right thickness) and then duct taped it to the front fork
2. I mounted it closer to the center of the wheel, as far as wire length permitted
Then I fixed the sensor in place using cable ties. The gap between sensor and magnet is more then 5 mm, and “the installation” does not look good. Nevertheless it’s working, and displaying all needed data.

Guys, thank you for your quick responses and help.

Here are pictures of the end result.
[img]http://www.bikeshake.com/wp-content/uploads/2011/01/DSC07503.JPG[/img]
[img]http://www.bikeshake.com/wp-content/uploads/2011/01/DSC07506.JPG[/img]

Weird about the wire length though. The wire that came with both the bc1609 and 1606L was long enough to wrap it many times around the brake cable. I don’t know about your bike’s setup, but maybe you could have mounted it closer to the center of the wheel? I know it’s working, but it would have been great if it looked good while working!

Judging by the fork and wheel alone, I have the impression that you have a beautiful bike. That’s why I ask about the wire length.

Installed the BC 1609 (wired version). Cadence works fine as does clock and temp but MPH, distance, etc do not work. I have it mounted on the front wheel about half way to the hub and the clearance seems to be OK.

It seems the sensor isn’t picking up the signal. To check that, turn the front wheel. Does the computer “wake up”? What’s the gap between the sensor and magnet?

If the computer’s still in standby mode, take off the magnet from the spoke, and make it touch the sensor several times. Does the computer wake up and start showing the speed? If not, there may be a problem with the cable.

You can upload some photos in the form below. This might help us determine the source of the problem.

Please post back with the results, as I’m curious to know what the problem is.

It seems the sensor isn’t picking up the signal. To check that, turn the front wheel. Does the computer “wake up”? What’s the gap between the sensor and magnet?

No effect.

If the computer’s still in standby mode, take off the magnet from the spoke, and make it touch the sensor several times. Does the computer wake up and start showing the speed? If not, there may be a problem with the cable.

Computer wake-up did not occur. Checked the cable for tautness and appears to be firmly attached to both the transducer and handlebar mount.

You can upload some photos in the form below. This might help us determine the source of the problem.

Two photos uploaded. The before pic showing the gap and the pic after I padded the transducer to take it closer to the magnet. In all cases, the mounting was about three inches from the hub.

Please post back with the results, as I’m curious to know what the problem is.

No matter if we did the before or after the result was the same. Temp, time and cadence worked fine. Nothing else did like speed, distance, etc. Seems like the cadence would not work if there were not a good electrical connection between the transducer and the computer.
Thanks in advance for your help.
Lee
[img]http://www.bikeshake.com/wp-content/uploads/2011/02/OrigInstall1Feb11-1.JPG[/img]
[img]http://www.bikeshake.com/wp-content/uploads/2011/02/PaddedInstallation1Feb11-1.JPG[/img]

In the first photo, the distance between the sensor and the magnet seems close enough. No need for padding, as in the second photo the magnet passes too close to the sensor.

Seems like the cadence would not work if there were not a good electrical connection between the transducer and the computer.

Actually, cadence has its own sensor, magnet and cable. The cadence sensor is installed on the chainstay. The cadence magnet goes on the pedal. The cable that goes from the cadence sensor to the computer can be connected/disconnected in the Sigma bc1609. The speed cable is permanently attached to the computer bracket on the handlebar on one end, and to the speed sensor on the fork on the other end.

Does the computer show cadence when you turn the wheel? If yes, then this means that you mounted the cadence sensor on the fork, instead of on the chainstay. I know of at least one guy who did that, so it’s entirely possible!

Apparently, what I have is a cadence sensor hard wired to the mount. The separate cadence sensor (which I have not hooked up)with the two connections looks exactly like the one I now have on the fork of my bike. The only thing that happens when I am underway is the cadence reading increases and decreases depending on speed (and of course, the clock and temp continue to work). No other motion seems to be sensed.

Is the cadence sensor and the speed/distance sensor the same device just used in separate ways or is the cadence sensor different physically from the speed/distance sensor?

Both sensors have exactly the same form factor — both have the name Sigma stenciled on the side. The sensor with the two connections has a serial or model number stamped on the top, 462P8. The sensor hard wired to the mount does not have any markings other than the name, Sigma.

OK, I tried every angle to remount the computer into the handle bar cradle. It fit the right way and it fit 180 degrees out of the right way. It would not lock in at any other angle.
In any case, it made no difference in the MPH or distance but the computer no longer registers cadence at all in any position.
Lee

I’m a little frustrated with the ghetto installation on this product, but I’ll take it out tomorrow and see how it works. If it works well, I’ll try to come up with something that looks better.

FWIW, I used the spacer that was intended for the cadence meter and strapped to the front fork, and it solved the problem. Probably the most frustrating thing about this situation is one, properly fabricated, 25 cent part, that they include for the cadence wire, would solve the problem.

I have a BC1609, and it fits perfectly to my MTB. Just 2 small problems which I need help with.. I have lost the paper operating instructions, and want to know 1, how to turn off/on when not in use, and 2, how to reset for each ride. It seems to be adding all the distances together. Any help would be greatly appreciated..

The computer turns off by itself several minutes after you stop using it. To reset, press the top left button for 2-3 seconds to reset the displayed value. To reset all the values, don’t release the top left button after the current value is reset. The computer will flash “Reset ALL” for 2 seconds and then will reset all the values.

Dave (varontron), Thanks for the info.
I installed the Sigma bc1609 on the stem myself, and I bent the connectors before connecting them, too.
Just to be sure, after installing, is the SIGMA inscription facing forwards or backwards now?

I have the BC 1609 bike computer and it has the cadance function, however, it is not working. I have positioned the sensor on the front fork (I believe correctly) and all the other functions are working well. Have I done something wrong? Does this computer have the cadance function? Can you suggest any ideas
Thanks

Hi Graham,
The Sigma BC1609 has the cadence option. But it is optional, which means you have to purchase the cadence sensor separately, like I did.
The cadence sensor should be mounted on the left chainstay near the bottom bracket. The magnet that comes with it is installed on the left crank arm. The sensor comes with a cable that connects to the computer’s handlebar mount.
If you have any more questions, I’ll be happy to help.

I have the BC 1609 STS + Cadence bike computer. I works as advertised. However, I have found that the auto-shut off feature does not appear to work. Minutes or hours after inactivity, the screen shows the computer model number and current time. Is this what it means to go into “rest” or “shut off”? I have had other computers that time out to a blank screen. If this display of model number and time will still provide a year of battey life, I am okay with this display not being blank.

Hi Rick,
When the computer is showing the time, it’s in standby mode (to which you refer as auto shut off). It’s completely normal. The battery life depends on the amount of riding you do. In the case of Sigma BC1609 (not STS), I had to change the battery once after a year of commuting about 1.5 hours per day. The STS is wireless, so the battery might not last as long.

I had an old sigma computer which I have replaced with the BC1609. The mount and wiring from the old computer still works with this computer. I have therefore installed the mount and wiring that came with this computer to my second bike. However I cannot see anyway to manually change to the 2nd bike wheel setting. Does anyone know if this can be done or do I have to buy the specific mount for a second bike? …..I think that makes sense! Cheers

I have just installed a wireless sigma 1609 and after fighting my way thrugh the instruction manual finally got it installed and working. It would be much better if all the English was together, Japaness together etc.
Any way my problem is that the computer works fine during the day but when I turn on my light (LED) it stops working. Sometimes it works when the light is on flashing mode.
Has anyone else encountered this problem and if so how did they resolve it.
I am going to try and move the light as far as possible from the display but as you are all probably aware there is not really a lot of room. I currently have the monitor on the stem

Stewart,
You might not be able to solve this with your computer/light combo, but here are some suggestions:
1. Move the light away (you were planning on doing this, I know). Maybe mount the light on the fork.
2. Mount the computer on the same side as the sensor and mount the light on the other side. For example, if the sensor is on the right fork blade, mount the computer on the right side of the handlebars, and the light on the left.
3. Wrap the light with aluminum foil and see if it helps. You can disassemble your light and try wrapping the components with Al foil. But be careful not to short anything out!

I need to mount my Sigma 1609 onto a secondary bike, so I will be only having the monitor with me but won’t be moving any of the cables. Do you guys know where I could how I could buy the accessories online or even go about to make these accessories?

complete piece of garbage. 5mm from sensor to magnet? no fricking way. I had to jury rig a system of wood blocks and duct tape to get it to work, and for 50 Swiss Franks (about 55 US dollars), I give this thing a ZERO star rating.

I love the Sigma 1609! It’s works flawlessly. The only issue I had (at first) was the distance between the sensor and the magnet (5mm was very hard to get). I ended up putting a few zipties underneath the sensor to make it stick out closer to the magnet and that worked. A little cleaner than using duct tape or wood chips IMO. Overall, just make sure you don’t confuse the cadence and front sensor wires. Also, make sure you get within that 5mm (be creative). Good luck!

Does it matter which side of the front fork the sensor is place in?!!!!!! I just recently bought the Sigma BC 1609 for my MB and like the mayority of the people on this site were having the same problem with the magnet. I just call Sigma and explain to them what was happening and ask them if I could get a bigger magnet. They said yes and there are sending me a bigger magnet. How big? Don’t know but I hope it works and if not I guess is up front and center with the black tape and ingenuity.

Curiosity
I installed the Sigma BC 1609 STS on a motorcycle Honda Vfr and having gone mad in order to understand the reason for the failure (for example, the distance between the magnet and sensor) I discovered that when I turn on the engine the sensor stops communicating with the computer. Going downhill with the motor off (downhill because the motorcycle weighs a lot) it works fine but not all streets are downhill. Thank goodness that is digital wireless. I bought a wireless cyclocomputer with solar cell and unknown brand in the supermarket at the modest price of 15 euros and it works fine. I have no words.
Ciao

I purchased this as my existing Cycle Computer did not have a Cadence function- though it had almost everything else on one screen.

Before installing the Sigma I read pretty much everything I could find -and believe me you need to as the manual is tiny and not easy to follow.

Anyhow, installation was reasonably straight forward: set-up wasn’t too bad and placing the components was Ok because you can use the provided o-rings to test various positions before committing to the also provided cable ties for more permanent placement.

At first the Cadence feature did not seem to work- but it seems you have to give it a fair number of revolutions before it registers. The Speed Sensor seemed fine from the outset.

Because I already had a computer on the front wheel I installed the Sigma Speed Sensor next to the Cadence Sensor on the rear chain stay. (This was still within Sigmas recommended distance range). I had also read that some LED lights interfere with the sensors- maybe being further away will make a difference??

The shape of the Speed Sensor meant that it didn’t fit quite as well as the Cadence Senor on the chain stay, so I packed out the inside of the chain stay with 4 pieces of rubber tape on top of each other and the same length as the Speed sensor before fixing with cable ties.

The Cadence Sensor magnet was fairly bulky, so instead of using this I used 2 rare earth magnets, which hold themselves magnetically to the bikes pedal axle and are very discrete. I also didn’t use the sigma speed magnet, but an old one from another computer- which seemed a better design. Onto this I superglued a small rare earth magnet of the same diameter in cas the magney was dodgy.

Before setting the Wheel Size I checked Sigmas table and was surprised to see that the stated circumference was considerably different to the one in my old Computer’s table -and from what I thought I remembered.

So I re-measured my wheel circumference. To do this I checked tyre inflation, put a small dab of white paint on the top of the front wheel and ran the wheel across the garage floor till I had 2 white spots. Then I measured the distance from dot start to dot start and found Sigma’s table did not match the measured distance. So I entered my tyre size in the settings.

The 1609 STS has nice big numbers, BUT Speed is always displayed #with an Up or Down arrow- meaning above or below Average Speed) plus one other function which you can select “on the fly”.

That’s it! You can scroll through the other functions, but can’t see them simultaneously.

However the many functions are all there and if you prefer an un-cluttered look this will suit you.

I would have preferred a scan function to roll through the functions every few seconds- but that’s me.

So at the moment I have 2 computers on-board which looks pretty nerdy, I guess- but I’m happy. Once I’m totally familiar with the 1609 I plan to get rid of the old one.
BTW on my test run of about 20 minutes everything worked fine with no interference. The read-outs of the 2 computers were almost identical.

I read somewhere that re-setting has to be done one feature at a time- this is incorrect, you simply hold the Reset button until Reset all? appears.
Changing the Sensor batteries requires a special 2 pronged tool which is provided but the computer needs only a coin!
Note to self- “Don’t lose tool”

I need help on where to place the wheel sensor. Is there a difference in culculation /OR will reading be inaccurate on where i place the sensor on the spokes of the wheel?

Meaning; if I place the sensor at the top of spokes near the rims, will i get the same reading measurements as compared to placing the sensor closer to the center of the wheel, near the hubs.

Will the reading of speed distance be the same?

Also, what do I need to make the wheel sensor closer to the fork sensor. It looks so messy and adds on to the weight by duct taping and putting in foreign objects, just to extent the sensor and closer up the Gap.

Hi Koo Kai Wen, Daniel,
You can place the wheel sensor anywhere you want on the spoke. It doesn’t affect the speed readings.
As for your second question about bringing the magnet (on the spoke) closer to the sensor (on the fork), try placing them further down (closer to the center of the wheel. If this doesn’t help, wrap an old inner tube on the fork to close the gap. To keep the inner tube from unwrapping by itself, use some duct tape. It won’t look ugly, especially if you use a thin inner tube.
If you need any further help, please write back and I’ll do my best to help you. You can upload photos via the form below if you need to.

I wonder how to get the cadence sensor to work without the speed sensor?

Anyone know if clipping the speed sensor wire will work?

The reason I ask is that the speed sensor is useless on my front wheel (on the stationary trainer) and the wire is too short to reach the back tire. So….. I’m hoping to somehow run it with *just* the cadence.

The computer head unit seems to fall asleep after 3:40 of inactivity (from the speed sensor) as well.